NMAD SV20H

Discuss the stuff that makes your ears bleed.

Moderators: Slowy, Capt. Black

goldtop0
Squier
Posts: 395
meble-kuchenne.warszawa.pl
Joined: Thu Oct 09, 2003 4:10 pm
Location: Auckland NZ
Has liked: 7 times
Been liked: 112 times

Re: NMAD SV20H

Post by goldtop0 »

Slowy wrote: Sun Jan 01, 2023 12:18 pm
goldtop0 wrote: Sun Jan 01, 2023 9:03 am ..... but is somewhat strident and piercing at volume
It's an EL34 amp. Isn't that what they do?


To a certain degree but not to the point of overpowering the senses :o
It's just a little too raspy on the bridge pup of my LP which is what I don't like, don't get that with my other Ms, 1974X and 1962.
Last edited by goldtop0 on Sun Jan 01, 2023 1:05 pm, edited 1 time in total.
Doin' that scrapyard thing.

goldtop0
Squier
Posts: 395
Joined: Thu Oct 09, 2003 4:10 pm
Location: Auckland NZ
Has liked: 7 times
Been liked: 112 times

Re: NMAD SV20H

Post by goldtop0 »

FuzzMonkey wrote: Sun Jan 01, 2023 11:52 am
goldtop0 wrote: Sun Jan 01, 2023 11:28 am With these 4 input Ms I tend to jump the channels and playing at high volume is not generally not the norm for me these days so relief at medium to lower volume playing is what I look for now.
The Bright cap on this one is 4.7nf apparently.
A 470pf/500pf might be what you are after if you blend the channels. It will still give you a bit of bite without the that super aggressiveness of the 4.7nf/4700pf.

After doing some research, the bright cap is soldered to the PCB that the pots are attached to so it would be a relatively simple mod. Famous last words; desolder the old cap and install the new one. I don't know how labour intensive removing the PCB from the chassis would be however.

The cathode arrangement on the bright channel, if what I read was true, is a 820R resistor bypassed by a 680nf cap. This also will thin things out a bit more than the 2.7k/680nf arrangement.


Thanks so much for your input Fuzz.
I'll talk with Clarry about this as like you he's got the nouse with all this techno stuff. He'll get the circuitry sorted and we'll take it from there.
Doin' that scrapyard thing.

User avatar
FuzzMonkey
Gibson
Posts: 611
Joined: Fri Nov 06, 2020 7:25 pm
Has liked: 510 times
Been liked: 407 times

Re: NMAD SV20H

Post by FuzzMonkey »

goldtop0 wrote: Sun Jan 01, 2023 1:02 pm Thanks so much for your input Fuzz.
I'll talk with Clarry about this as like you he's got the nouse with all this techno stuff. He'll get the circuitry sorted and we'll take it from there.
No worries. Let us know how you get on and which way you decide to go.
"There's no creativity without vulnerability."

www.fantailaudio.com

User avatar
Slowy
Vintage Post Junkie
Vintage Post Junkie
Posts: 22638
Joined: Wed Sep 09, 2009 4:13 pm
Location: Orcland
Has liked: 1011 times
Been liked: 2466 times

Re: NMAD SV20H

Post by Slowy »

goldtop0 wrote: Sun Jan 01, 2023 12:57 pm
Slowy wrote: Sun Jan 01, 2023 12:18 pm
goldtop0 wrote: Sun Jan 01, 2023 9:03 am ..... but is somewhat strident and piercing at volume
It's an EL34 amp. Isn't that what they do?


To a certain degree but not to the point of overpowering the senses :o
It's just a little too raspy on the bridge pup of my LP which is what I don't like, don't get that with my other Ms, 1974X and 1962.
Got an EQ like a Boss GS-7 handy? Pull out the uglies and have a listen to what's left. :D
Beyond a critical point within a finite space, freedom diminishes as numbers increase. This is as true of humans as it is of gas molecules in a sealed flask. The human question is not how many can possibly survive within the system, but what kind of existence is possible for those who so survive.

User avatar
FuzzMonkey
Gibson
Posts: 611
Joined: Fri Nov 06, 2020 7:25 pm
Has liked: 510 times
Been liked: 407 times

Re: NMAD SV20H

Post by FuzzMonkey »

The other thing that a bright cap of that size does is bring on the gain a lot faster.
"There's no creativity without vulnerability."

www.fantailaudio.com

Optical
Tokai
Tokai
Posts: 419
Joined: Thu Nov 24, 2016 4:34 pm
Has liked: 67 times
Been liked: 142 times

Re: NMAD SV20H

Post by Optical »

FuzzMonkey wrote: Sun Jan 01, 2023 12:45 pm
Optical wrote: Sun Jan 01, 2023 12:31 pmThe 820R value is thicker/more bass/less treble shelving than the 2k7 but yeah
I believe the 820R/680nf was featured in the early Marshalls with the split cathode arrangement before they went to the more common 2.7k/680nf arrangement. The 820R/680nf rolls off the lower frequencies from 285Hz downwards and 2.7k/680nf from around 86Hz.
No that's not quite right.. the resistor sets the unbypassed gain, lower values are more gain.
There's about 12 different superlead circuit variations, maybe more? The famous evh amp had 820R//680n on the first stage but I'm not sure if that was ever a factory config, but who knows with Marshalls ambivalence to part values

goldtop0
Squier
Posts: 395
Joined: Thu Oct 09, 2003 4:10 pm
Location: Auckland NZ
Has liked: 7 times
Been liked: 112 times

Re: NMAD SV20H

Post by goldtop0 »

Slowy wrote: Sun Jan 01, 2023 4:35 pm
goldtop0 wrote: Sun Jan 01, 2023 12:57 pm
Slowy wrote: Sun Jan 01, 2023 12:18 pm



Got an EQ like a Boss GS-7 handy? Pull out the uglies and have a listen to what's left. :D


Not a fan of using pedals etc, but thanks for the suggestion :)
Doin' that scrapyard thing.

User avatar
FuzzMonkey
Gibson
Posts: 611
Joined: Fri Nov 06, 2020 7:25 pm
Has liked: 510 times
Been liked: 407 times

Re: NMAD SV20H

Post by FuzzMonkey »

Optical wrote: Sun Jan 01, 2023 6:56 pmNo that's not quite right.. the resistor sets the unbypassed gain, lower values are more gain.
There's about 12 different superlead circuit variations, maybe more? The famous evh amp had 820R//680n on the first stage but I'm not sure if that was ever a factory config, but who knows with Marshalls ambivalence to part values
That isn't quite right is it? Thanks for pointing that out for me; I stand corrected.

My brain for some reason failed to take into account the difference in gain and just saw the filtering side of things without taking into account the effect of the different resistor values. One has more gain at a higher cut-off and the other less gain at a lower cut-off. So I imagine the actual tonal response would be similar. I need to find one of those online calculators to satisfy my curiosity now.
"There's no creativity without vulnerability."

www.fantailaudio.com

goldtop0
Squier
Posts: 395
Joined: Thu Oct 09, 2003 4:10 pm
Location: Auckland NZ
Has liked: 7 times
Been liked: 112 times

Re: NMAD SV20H

Post by goldtop0 »

One thing is, don't use the amp with the SV112 cab as that single 12" enclosure is not great at all as I kind of expected, use a 2x12.
And...........it retails at $995, not a good look and well overpriced. A classic case of aesthetics over usefulness and efficiency.
Doin' that scrapyard thing.

User avatar
MikeC
Vintage Post Junkie
Vintage Post Junkie
Posts: 2938
Joined: Fri Sep 12, 2003 5:43 pm
Location: Red Beach, Auckland
Has liked: 1309 times
Been liked: 867 times

Re: NMAD SV20H

Post by MikeC »

Optical wrote: Sun Jan 01, 2023 6:56 pm
FuzzMonkey wrote: Sun Jan 01, 2023 12:45 pm
Optical wrote: Sun Jan 01, 2023 12:31 pmThe 820R value is thicker/more bass/less treble shelving than the 2k7 but yeah
I believe the 820R/680nf was featured in the early Marshalls with the split cathode arrangement before they went to the more common 2.7k/680nf arrangement. The 820R/680nf rolls off the lower frequencies from 285Hz downwards and 2.7k/680nf from around 86Hz.
No that's not quite right.. the resistor sets the unbypassed gain, lower values are more gain.
There's about 12 different superlead circuit variations, maybe more? The famous evh amp had 820R//680n on the first stage but I'm not sure if that was ever a factory config, but who knows with Marshalls ambivalence to part values
This :). And the bypass cap allows certain frequencies thru as is there is no resistor. Those frequencies get even more amplified by the stage!
Whakanuia o mea kei a koe

User avatar
codedog
Vintage Post Junkie
Vintage Post Junkie
Posts: 6705
Joined: Wed Jun 11, 2014 8:44 pm
Location: Christchurch
Has liked: 3476 times
Been liked: 1083 times

Re: NMAD SV20H

Post by codedog »

Just saw an SV20C on Facebook. That's a 1x12 combo, I think?

User avatar
FuzzMonkey
Gibson
Posts: 611
Joined: Fri Nov 06, 2020 7:25 pm
Has liked: 510 times
Been liked: 407 times

Re: NMAD SV20H

Post by FuzzMonkey »

codedog wrote: Tue Jan 03, 2023 2:47 pm Just saw an SV20C on Facebook. That's a 1x12 combo, I think?
1x10 unfortunately. I'm not sure why Marshall insist on putting 10" speakers in their lower-wattage combo amp.
"There's no creativity without vulnerability."

www.fantailaudio.com

User avatar
Bg
Site Admin
Posts: 43187
Joined: Fri Sep 05, 2003 12:13 am
Location: Auckland
Has liked: 2254 times
Been liked: 3873 times

Re: NMAD SV20H

Post by Bg »

FuzzMonkey wrote: Tue Jan 03, 2023 3:18 pm
codedog wrote: Tue Jan 03, 2023 2:47 pm Just saw an SV20C on Facebook. That's a 1x12 combo, I think?
1x10 unfortunately. I'm not sure why Marshall insist on putting 10" speakers in their lower-wattage combo amp.
Depends on the 1x10, nothing wrong with a 10" jensen alnico
So, is that low alcohol or no alcohol at all? mmmm, no alcohol, do you want to try it? Noooooooooo.

User avatar
FuzzMonkey
Gibson
Posts: 611
Joined: Fri Nov 06, 2020 7:25 pm
Has liked: 510 times
Been liked: 407 times

Re: NMAD SV20H

Post by FuzzMonkey »

Bg wrote: Tue Jan 03, 2023 3:36 pm
FuzzMonkey wrote: Tue Jan 03, 2023 3:18 pm
codedog wrote: Tue Jan 03, 2023 2:47 pm Just saw an SV20C on Facebook. That's a 1x12 combo, I think?
1x10 unfortunately. I'm not sure why Marshall insist on putting 10" speakers in their lower-wattage combo amp.
Depends on the 1x10, nothing wrong with a 10" jensen alnico
True. I believe it is a 10" Celestion V-Type in the combo version of the Studio Vintage. Maybe a 10" Greenback would be a nice, amp-correct upgrade.
"There's no creativity without vulnerability."

www.fantailaudio.com

User avatar
Bg
Site Admin
Posts: 43187
Joined: Fri Sep 05, 2003 12:13 am
Location: Auckland
Has liked: 2254 times
Been liked: 3873 times

Re: NMAD SV20H

Post by Bg »

yep that would make more sense for the amp
So, is that low alcohol or no alcohol at all? mmmm, no alcohol, do you want to try it? Noooooooooo.

Post Reply